Wheel hub assemblies with anti-rotate feature for use with zero-radius-turning vehicle

ABSTRACT

The present invention provides a hub assembly and a hub fastener anti-rotate apparatus for securing a wheel of vehicle (e.g., a zero-radius-turning lawn mower) to a vehicle drive axle. The anti-rotate apparatus may assist in preventing or substantially limiting loosening of a hub fastener used to secure the hub assembly to the drive axle.

TECHNICAL FIELD

[0001] The present invention relates generally to a zero-radius-turning(ZRT) ground maintenance vehicle such as a ZRT riding mower and, moreparticularly, to wheel hub assemblies having anti-rotate features foruse with such a vehicle.

BACKGROUND

[0002] Traditional riding mowers, e.g., those typically having fourwheels wherein the front wheels are conventionally steerable, are incommon use by homeowners and professionals alike. However, for lawnshaving numerous obstacles, tight spaces, and/or intricate borders,riding mowers having zero-radius-turning (ZRT) capability are oftenpreferred. As the name implies, “ZRT” generally indicates a vehiclehaving a very tight minimum turning radius, i.e., a vehicle that ishighly maneuverable.

[0003] Most ZRT riding mowers have one or more drive wheels located oneach side of the mower. The drive wheels are independently powered,e.g., by hydraulic motors or integrated zero-turn transaxles, so that,while a drive wheel on a first side of the mower may rotate in a firstdirection at a first speed, the drive wheel on the opposite side mayrotate in the same or different direction at the same or differentspeed. Rotating one drive wheel for forward motion while simultaneouslyslowing, stopping, or reversing rotation of the drive wheel on theopposite side, causes the mower to turn. At the extreme, the mower mayspin generally about a vertical axis located between the respectivedrive wheels.

[0004] Each drive wheel is typically coupled to a drive shaft or axle ofa mower with a hub. The hub may include a flange having a conventionallug pattern to which the wheel attaches.

[0005] Often, the hub is attached to the drive axle with a coaxialfastener or mounting bolt and transfers rotational power through matingsurfaces provided on both the axle and the hub. While this configurationis adequate for many applications, the frequent speed and directionchanges common with ZRT mowers may cause the coaxial bolt to back out orloosen over time. This problem may be more apparent where theconfiguration of the hub and axle mating surfaces allows for greaterrotational movement of the hub relative to the axle.

[0006] As a result, many ZRT mowers that utilize a central mounting boltalso utilize a hub/axle combination having relatively tight clearances,i.e., having minimal backlash or “looseness,” between the matingsurfaces of the drive axle and the hub. Thus, relative motion betweenthe axle and the hub is minimized, reducing the tendency for themounting bolt to inadvertently loosen over time. Some configurationsthat provide such tight clearances include, for example, an axle and hubusing a key and keyway to transfer torque. Other configurations mayutilize a tapered axle and hub combination, where the axle transferstorque to the hub via the interference fit between the two components.Other options include permanently securing the hub to the axle, such asby welding. All these configurations provide minimal backlash and, thus,may be effective in limiting the loosening effect on the mounting boltduring mower operation.

[0007] While effective at reducing backlash, these hub and axleconfigurations are potentially expensive to produce. Although the costmay be acceptable for larger, commercial grade equipment, it may beeconomically undesirable for smaller mowers, e.g., those directedprimarily to homeowners. Moreover, smaller ZRT mowers may not have adrive axle of sufficient diameter to accommodate the desired keyway ortaper configuration.

[0008] Another technique known for preventing loosening between twocomponents is lockwiring. While effective, lockwiring can belabor-intensive and require a certain level of skill to properlyinstall. In addition, lockwire is usually destroyed upon removal, i.e.,it is generally not reusable.

SUMMARY

[0009] The present invention provides wheel hub assemblies andanti-rotate apparatus for use with ZRT vehicles that overcome theabove-identified problems. In particular, the present invention provideshub assemblies attachable to a drive axle with a coaxial hub fastener.Each hub assembly includes an anti-rotate apparatus that substantiallyrestricts or eliminates relative motion between the hub fastener and ahub portion of the hub assembly.

[0010] In one embodiment, a wheel hub assembly for attachment to a driveaxle of a zero-radius-turning mower is provided. The hub assemblyincludes a hub having a central opening with one or more drive axlereceiving surfaces, and a hub fastener operable to axially secure thehub to the drive axle. An anti-rotate apparatus having at least onethreaded retaining fastener is also included. The anti-rotate apparatussubstantially restricts or prevents rotation of the hub fastenerrelative to the hub when the hub is attached to the drive axle.

[0011] In another embodiment, a wheel hub assembly for coupling a wheelto a drive axle of a zero-radius-turning vehicle is provided. The hubassembly includes a hub having a central opening with a drive axlereceiving surface, and a hub fastener coaxial with an axis of the driveaxle. The hub fastener is operable to axially retain the hub relative tothe drive axle. An anti-rotate apparatus including an anti-rotate memberand at least one threaded retaining fastener is also included. Theanti-rotate apparatus is operable to substantially limit or preventrelative rotation between the hub fastener and the hub when the hub isattached to the drive axle.

[0012] In yet another embodiment, an anti-rotate apparatus operable toprevent loosening of a hub fastener used to secure a wheel hub to adrive axle of a zero-radius-turning vehicle is provided. The anti-rotateapparatus includes a hub fastener anti-rotate member; and a threadedretaining fastener operable to secure the anti-rotate member relative tothe hub.

[0013] In still yet another embodiment, an anti-rotate apparatusoperable to prevent loosening of a hub fastener used to secure a wheelhub to a drive axle of a zero-radius-turning vehicle is provided. Theanti-rotate apparatus includes means for engaging the hub fastener, anda threaded retaining fastener operable to secure the means for engagingthe hub fastener relative to the hub.

[0014] The above summary is not intended to describe each embodiment orevery implementation of the present invention. Rather, a more completeunderstanding of the invention will become apparent and appreciated byreference to the following detailed description and claims in view ofthe accompanying drawing.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWING

[0015] The present invention will be further described with reference tothe views of the drawing, wherein:

[0016]FIG. 1 is a perspective view of a portion of a zero-radius-turning(ZRT) vehicle, e.g., a mower, having a wheel and wheel hub assembly inaccordance with one embodiment of the present invention;

[0017]FIG. 2 is an enlarged view of the wheel hub assembly of FIG. 1with the wheel detached;

[0018]FIG. 3 is an exploded view of the wheel hub assembly of FIG. 2illustrating with particularity an anti-rotate apparatus in accordancewith one embodiment of the invention;

[0019]FIG. 4 is a side elevation view of a hub portion of the wheel hubassembly of FIG. 3;

[0020]FIG. 5 is a section view of the hub portion of FIG. 4 taken alongline 5-5;

[0021]FIG. 6 is an enlarged view of a bearing member, e.g., washer, ofthe hub assembly of FIG. 3;

[0022]FIG. 7 is an enlarged view of an anti-rotate member, e.g., locktab, of the anti-rotate apparatus of FIG. 3;

[0023]FIG. 8 is a side elevation view of a wheel and wheel hub assemblyin accordance with another embodiment of the present invention;

[0024]FIG. 9 is a section view of the wheel and wheel hub assembly ofFIG. 8 taken along line 9-9;

[0025]FIG. 10 is an exploded view of the wheel hub assembly of FIG. 8illustrating an anti-rotate apparatus in accordance with anotherembodiment of the invention;

[0026]FIG. 11 is an enlarged view of a bearing member, e.g., washer, ofthe anti-rotate rotate apparatus of FIG. 10;

[0027]FIG. 12 is a section view of the washer of FIG. 11 taken alongline 12-12;

[0028]FIG. 13 is a partial exploded view of a wheel hub assembly andassociated anti-rotate apparatus in accordance with yet anotherembodiment of the present invention;

[0029]FIG. 14 is an enlarged view of an anti-rotate member, e.g., clamp,of the anti-rotate apparatus of FIG. 13; and

[0030]FIG. 15 is a section view of the anti-rotate member of FIG. 14taken along line 15-15.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0031] In the following detailed description of exemplary embodiments,reference is made to the accompanying views of the drawing which form apart hereof, and in which are shown by way of illustration specificembodiments in which the invention may be practiced. It is to beunderstood that other embodiments may be utilized and structural changesmay be made without departing from the scope of the present invention.

[0032] Generally speaking, the invention described herein is directed toa wheel hub assembly advantageous for use with a zero-radius-turning(ZRT) riding mower. The hub assembly includes a hub that may secure toan end of a powered drive axle with a coaxial hub fastener, e.g., bolt.To prevent loosening of the hub fastener, hub assemblies of the presentinvention may include an anti-rotate apparatus which substantiallyrestricts or eliminates relative motion between the hub fastener and thehub. As a result, the hub fastener preferably does not loosen when thehub assembly is subjected to the numerous speed changes and directionalreversals often associated with operation of ZRT vehicles.

[0033]FIG. 1 illustrates a hub assembly 200 in accordance with oneembodiment of the present invention as it may be incorporated on anexemplary self-propelled, ground maintenance vehicle, e.g., a ZRT ridinglawn mower 100 (also referred to herein simply as a “mower”). While theinvention is herein described with respect to riding ZRT mowers, thoseof skill in the art will realize that the invention is also applicableto other mowers (e.g., walk-behind), and to other vehicles, especiallythose having ZRT capability, such as skid-steer loaders and otherconstruction or excavation vehicles.

[0034] While the present invention is not limited to any particularmower configuration, an exemplary ZRT mower that may incorporate thewheel hub assembly of the present invention is briefly described below.

[0035] A left and a right ground-engaging drive wheel 102 (only leftwheel shown in FIG. 1) may be rotatably coupled to left and right sidesof the mower 100, respectively. The drive wheels 102 may beindependently powered by an engine (not shown), e.g., via one or morehydraulic motors, transmissions, transaxles, or the equivalent, so thatthe drive wheels 102 may propel the mower 100 along a ground surface 105during operation. A pair of front swiveling caster wheels (not shown)may support a front portion of the mower 100 in rolling engagement withthe ground surface 105.

[0036] One or more controls, e.g., left and right drive control levers106 (left lever shown in FIG. 1 displaced outwardly for operatoringress/egress) are also provided. The drive control levers 106 aregenerally pivotally coupled to a frame of the mower 100, e.g., such thatthey may pivot forwardly and rearwardly under the control of an operatorsitting in an operator's seat 108. Each drive control lever 106 isoperable to independently control speed and direction of the respectivedrive wheel 102 via manipulation of the mower's drive system as is knownin the art. For example, incremental forward movement (e.g., pivotingabout a transverse horizontal axis) of the left (or right) drive controllever 106, from a neutral position, results in an incremental increasein rotational speed of the left (or right) drive wheel 102 in a forwarddirection. Similarly, incremental rearward movement of the left (orright) drive control lever 106, from a neutral position, results in anincremental increase in rotational speed of the left (or right) drivewheel 102 in a rearward direction.

[0037] A cutting deck 110 may be mounted to a lower side of the mower100. The cutting deck 110 includes one or more cutting blades (notshown), as known in the art, that are operatively powered by the engine.Miscellaneous controls (also not shown) may be provided to allowoperator control of various mower functions, e.g., throttle, bladeengagement, cutting deck height, etc. During operation, power isselectively delivered to the cutting deck 110 and the drive wheels 102,whereby the cutting blades rotate at a speed sufficient to sever grassand other vegetation as the cutting deck 110 passes over the groundsurface 105.

[0038]FIG. 2 is an enlarged partial view of the mower 100 showing thewheel hub assembly 200 (wheel 102 removed for clarity). As is known inthe art, a wheel motor 112, e.g., hydraulic motor, having a drive axle114 may be provided to deliver rotational power to the wheel 102. Thehub assembly 200 may be coupled to a distal end 116 (see FIG. 3) of theaxle 114 as further described below.

[0039] The hub assembly 200 may include a hub 201 having a body or bodyportion 202 and a flange or flange portion 204. In the illustratedembodiment, the flange portion 204 provides threaded holes 206 whichdefine a lug pattern designed to receive and support the wheel 102 withthe use of fasteners 208.

[0040]FIG. 3 is an exploded view of the wheel hub assembly 200 of FIGS.1 and 2. As illustrated in this view, the distal end 116 of the axle 114may include a coaxial threaded hole 120 to receive a hub fastener orbolt 214. One or more surfaces, e.g., flat surfaces 118, may be providedproximate the distal end 116. The flat surfaces 118 may engagecorresponding drive axle receiving surfaces, e.g., diametrically opposedflat surfaces 213, formed in a central opening 210 of the hub body 202when the hub 201 is attached to the axle 114.

[0041] To attach the hub 201 to the axle 114, a bearing member, e.g.,washer 212, having a clearance hole 211 is provided. The hub fastener214 may pass through the clearance hole 211 and thread into the threadedhole 120. While the invention is not limited to any particular componentsizes, the axle 114 may be approximately 0.75 inch in diameter and thehub fastener 214 and threaded hole 120 may have a {fraction (5/16)}-24UNF thread. Moreover, the distance across the flat surfaces 118 may beabout 0.56 inches.

[0042]FIG. 3 further illustrates an anti-rotate apparatus 225 inaccordance with one embodiment of the invention. The anti-rotateapparatus 225 may include a hub fastener anti-rotate member and aretaining fastener 224. While the anti-rotate member may take variousforms, it is, in one embodiment, a generally flat and oblong-shaped locktab 220. As further described below, the retaining fastener 224 may bethreaded and secure the lock tab 220 to the hub 201 by threadablyengaging an anchor or anchor portion 218. In the illustrated embodiment,the anchor 218 is integrally formed with (e.g., welded to) the hub 201.However, other embodiments may utilize different configurations, e.g., aremovable anchor portion, as described below.

[0043] The anchor 218 may include a threaded hole 230 sized tothreadably receive the retaining fastener 224, which, in one embodiment,has a ¼-20 UN thread. The washer 212 may include a flat edge 216 toallow flush contact with the hub 201 without interference from theanchor 218 as shown in FIGS. 2 and 5.

[0044] The lock tab 220 may include a first opening 222 having one ormore engagement portions operable to interlock and engage a head of thehub fastener 214 such that little or no relative rotation occurs betweenthe two components. In the illustrated embodiment, the engagementportions are formed by serrations or notches 222 a on an inner portion(see FIG. 7) of the first opening 222. These notches 222 a areconfigured to engage corners of the head of the hub fastener 214.

[0045] The lock tab 220 may also include a second opening 226 throughwhich the retaining fastener 224 may pass in order to secure the locktab 220 to the hub 201. The second opening 226 may provide clearance forthe retaining fastener 224 and may be oversized, e.g., slotted, topermit alignment and engagement of the fastener 224 with the threadedhole 230.

[0046]FIG. 4 is an elevation view of the hub 201 clearly illustratingthe body portion 202, the flange portion 204 with threaded holes 206,the anchor 218 with threaded hole 230, and the central opening 210 andthe mating surfaces 213. While the mating surfaces 213 are shown asgenerally two diametrically opposed flats formed in the central opening210 (sometimes referred to as a “double-D” configuration), other matingsurface configurations are also possible. In fact, most any engagementsurface configuration that provides for torque transfer between the axle114 and the hub 201 is possible without departing from the scope of theinvention.

[0047]FIG. 5 is a section view of the hub 201 illustrating, amongothers, the relative positions of the washer 212 (in phantom lines) andthe anchor 218 when the hub assembly 200 is attached to the axle 114(not shown in this view). The anti-rotate apparatus 225 and the hubfastener 214 are also illustrated in this view in phantom lines. Whilethe flat 216 of the washer 212 is beneficial to avoid interference fromthe anchor 218, other embodiments could locate the anchor 218 outsidethe envelope of the washer 212. In such embodiments, a generally roundwasher 212 may be used.

[0048]FIG. 5 further illustrates the central bore 210 and the surfaces213. Except in the vicinity of the surfaces 213, the central bore 210may be substantially cylindrical in shape as identified by the region215. As a result, the hub 201 may slide over the axle 114 until a face122 (formed by the transition of the flat surfaces 118 to the round axle114 as shown in FIG. 3) of the axle contacts a surface 232 of the hub201.

[0049]FIG. 6 is an enlarged view of the washer 212, and FIG. 7 is anenlarged view of the lock tab 220. FIG. 7 clearly illustrates thenotches 222 a within the first opening 222, as well as the slottedsecond opening 226.

[0050] To install the hub assembly 200 of FIGS. 1-3, the hub 201 is slidover the distal end 116 of the axle 114 (see FIG. 3). The hub 201 may berotated to permit the flats 118 of the axle 114 (see FIG. 3) to engagethe corresponding surfaces 213 (see FIG. 5) of the hub 201. The hub 201may then slide axially until the face 122 (see FIG. 3) of the axle 114contacts the surface 232 (see FIG. 5) of the hub 201. Preferably, thedistal end 116 of the axle 114 remains within the central opening 210,i.e., it does not extend outside the hub 201, when the surface 232contacts the face 122.

[0051] The washer 212 may then be located over the central opening 210of the hub 201 adjacent the distal end 116 of the axle 114 and rotateduntil the flat 216 seats around the anchor 218 as illustrated in FIG. 5.The hub fastener 214 (see FIG. 3) may then be passed through theclearance hole 211 of the washer 212 and threaded into the threaded hole120 (see also FIG. 3). After tightening the hub fastener 214 to thedesired torque (which may be about 225 in-lbs for the {fraction (5/16)}inch fastener) the first opening 222 of the lock tab 220 (see FIG. 7)may be placed over the head of the hub fastener 214 such that the secondopening 226 aligns with the threaded hole 230 of the anchor 218. Theretaining fastener 224 may then be passed through the opening 226 andthreadably engaged with the threaded hole 230.

[0052] After tightening the retaining fastener 224 to the desiredtorque, the wheel 102 may be positioned adjacent the hub assembly 200and the lug pattern aligned with the threaded holes 206 of the flange204. Lug fasteners 208 (see FIG. 2) may then be passed through the wheel102, threaded into the threaded holes 206, and torqued appropriately.

[0053] During operation, forces that would otherwise tend to loosen thehub fastener 214 are at least partially reacted by the anti-rotateapparatus 225. These forces may be caused by, for example, backlashbetween the hub 201 and the axle 114. Such loosening loads may also becaused or magnified by axial loading of the hub 201 against the hubfastener 214. Such axial loading may result from various operatingconditions, e.g., operation of the mower 100 laterally across aninclined surface. However, with the anti-rotate apparatus 225 in place,any tendency of the hub fastener 214 to rotate relative to the hub 201is substantially reacted by the lock tab 220, which is itself fastenedto the hub 201 by the fastener 224.

[0054]FIGS. 8-12 illustrate a wheel hub assembly 300 in accordance withanother embodiment of the invention. In this embodiment, a hub 301 ofthe hub assembly 300 is permanently attached to its wheel 303, i.e., itis not intended for subsequent removal from, after initial attachmentto, the wheel 303. The hub 301 may be coupled to the wheel 303 in anynumber of ways including, for example, welding, threading, staking, orany other method that provides a generally fixed connection between thetwo components.

[0055] Like the hub 201 described above, the hub 301 includes a centralopening 310 (see FIG. 8) operable to receive the axle 114 (see FIG. 1).The central opening 310 may also include surfaces, e.g., dual flatsurfaces 313 (generally identical to surface 213 described above),operable to engage the axle surfaces 118 (see FIG. 1). The centralopening 310 may also include a generally cylindrical portion, identifiedby reference numeral 315 in FIG. 9, to accommodate the cylindricalportion of the axle 114. A surface 332, formed by the transition betweenthe cylindrical portion 315 and the surfaces 313, may assist in axiallylocating the hub assembly 300 relative to the axle 114.

[0056]FIG. 10 is an exploded view the hub assembly 300 of FIGS. 8 and 9.As with the hub assembly 200 described above, the hub 301 is operable toslide over the distal end 116 of the axle 114 until the face 122 (seeFIG. 3) of the axle contacts the surface 332 (see FIG. 9). Contactbetween the face 122 and the surface 332 preferably occurs before thedistal end 116 protrudes beyond the hub 301. To secure the hub 301axially to the axle 114, the hub assembly 300 may also include the hubfastener 214 as already described above.

[0057] The hub 301 may also include one or more first engagementportions, e.g., slots 317, the purpose of which is explained below.While various configurations are possible, the first engagement portionsof the illustrated embodiment are defined by two slots 317 formed atdiametrically opposed locations on an outer edge of the hub 301.However, this configuration is not limiting as any number of slots, orother engagement configurations, are possible.

[0058] The hub assembly 300 further includes an anti-rotate apparatus325 that functions in a manner similar to the anti-rotate apparatus 225described above. For example, the anti-rotate apparatus 325 may includean anti-rotate member, e.g., the lock tab 220. The lock tab 220 includesthe first opening 222 with notches 222 a (see FIG. 7) operable to engagethe head of the hub fastener 214, and the second opening 226. Theapparatus 325 may further include the fastener 224 operable to securethe lock tab 220, via the second opening 226, to the hub 301.

[0059] The anti-rotate apparatus 325 may further include a bearingmember located between a head of the hub fastener 214 and the face ofthe hub 301. In the illustrated embodiment, the bearing member isconfigured as an oblong washer 312. The washer 312 is illustrated indetail in FIGS. 11 and 12. Like the washer 212, the washer 312 mayinclude a clearance hole 311 to receive the hub fastener 214. However,unlike the washer 212, the washer 312 may also include an anchor portion318 having a threaded hole 330 operable to threadably receive theretaining fastener 224. Moreover, the washer 212 may further include oneor more second engagement portions, e.g., tabs 316, which are furtherdescribed below.

[0060] To attach the hub assembly 300 to the axle 114, the hub 301 maybe slid over the axle and rotated until the flats 118 engage thesurfaces 313 as already described above. The washer 312 may then beplaced over the end of the hub 301, as indicated in FIG. 10, andpositioned such that the tabs 316 engage the slots 317. The hub fastener214 may then be inserted through the opening 311 of the washer 312,threaded into the hole 120 (see FIG. 1), and tightened to the desiredtorque value. Once the hub fastener is tightened to the axle 114, thetabs 316 are securely retained within the slots 317. As a result, thewasher 312 is substantially rotationally secured relative to the hub 301such that it experiences little or no rotation relative to the hub 301.

[0061] The first opening 222 of the lock tab 220 may then be placed overthe head of the hub fastener 214 such that the second opening 226 of theanti-rotate washer aligns with the threaded hole 330 of the anchorportion 318 of the washer 312. The retaining fastener 224 may then bepassed through the second opening 226, threadably engaged with thethreaded hole 330, and torqued appropriately. Thus, in a manner similarto the anti-rotate assembly 225 described above, the anti-rotateapparatus 325 provides resistance to loosening of the hub fastener 214relative to the axle 114 during operation.

[0062]FIGS. 11 and 12 illustrate the tabs 316. The tabs 316 may beintegrally formed with or, alternatively, attached to, the washer 312 bymost any process including, for example, machining or welding. Moreover,while one particular embodiment is illustrated in the figures, otherengagement techniques may be utilized to rotationally secure the washer312 relative to the hub 301. For example, the tabs 316 and slots 317could be reversed, e.g., tabs on the hub 301 and slots on the washer312. Alternatively, the washer 312 could attached to the hub 301 withother fasteners rather than the tabs and slots. In fact, most anytechnique that substantially rotationally secures the washer 312relative to the hub 301 is possible without departing from the scope ofthe invention.

[0063]FIG. 13 illustrates a hub assembly 400 having an anti-rotateapparatus 425 in accordance with yet another embodiment of theinvention. The hub assembly 400 may include a hub 401 similar inconstruction to either the hub 201 or the hub 301 already describedherein. However, in this embodiment, neither the engagement portions,e.g., slots 317 (see FIG. 10), or the anchor 318 (see FIG. 3) arerequired.

[0064] The hub 401 preferably includes a central opening 410 to receivethe distal end 116 of the axle 114 as already described herein. The hubassembly 400 may also include a bearing member, e.g., washer 412, toprovide a bearing surface for the hub fastener 214. The hub 401 may besecured to the axle 114 with the washer 412 and hub fastener 214substantially as described elsewhere herein, see e.g., description ofwasher 212 and fastener 214 above.

[0065] The anti-rotate apparatus 425 of FIG. 13 may include ananti-rotate member, e.g., clamp 420, and a threaded retaining fastener424. The clamp 420 may include a first opening 442 shaped to engage thehead of the hub fastener 214. The first opening 442 may be formed by,for example, broaching or machining to form a generally hexagon-shapedopening as shown in FIGS. 13 and 14. The clamp 420 may also include asecond opening 440 operable to receive the retaining fastener 424. Inone embodiment, the length of the retaining fastener 424 is selectedsuch that it protrudes from the opposite side of the clamp 420 asufficient distance to permit it to threadably engage a nut 426.Alternatively, the second hole 420 may, on the opposite side of theclamp 420, have a thread formed therein for receiving the retainingfastener 424, in which case the nut 426 would not be required.

[0066] A longitudinal slot 444 extends from the first opening 442radially outward as shown in FIG. 14, thereby separating portions 420 aand 420 b of the clamp 420. As further described below, the slot 444permits deflection, e.g., clamping, of the clamp 420 when the retainingfastener 424 is tightened. That is, the longitudinal slot 444 permitsthe portions 420 a and 420 b to move towards one another, e.g., deflect,when the retaining fastener 424 is tightened. As the portions 420 a and420 b move toward one another, the size of the first opening 442 isreduced. The clamp 420 may be made of most any material that allowssufficient deflection without failure. For example, in one embodiment,the clamp 420 is made of aluminum.

[0067]FIG. 15 illustrates a section view of the anti-rotate member 420taken along line 15-15 of FIG. 14. As this view illustrates, the firstopening 442 transitions to a generally cylindrical surface 446 of adiameter that permits receipt of the external diameter of the hub 401with a slight clearance fit. The transition preferably forms a surface448 that may abut a face 449 (see FIG. 13) of the hub 401 when the clamp420 is attached.

[0068] The clamp 420 may include other features. For example, cutouts450 may be provided on each portion 420 a, 420 b. The cutouts 450 may beprovided for any number of reasons, e.g., manufacturing or engineeringrequirements, aesthetics, etc.

[0069] To install the hub assembly 400, the hub 401 may be slid over theaxle 114 as already described herein. The washer 412 may be positionedover the end of the hub 401, after which the hub fastener 214 may bethreaded into the axle 114 and tightened to the appropriate torquelevel. The clamp 420 may then be slid over the external diameter of thehub 401 and rotated until the head of the hub fastener 214 seats withinthe first opening 442 of the clamp 420 and the surface 448 of the clampcontacts the face 449 of the hub 401. The retaining fastener 424 maythen be inserted into the second opening 440 and tightened. As theretaining fastener 424 is tightened, the portions 420 a and 420 b (seeFIG. 14) move towards one another, i.e., the longitudinal slot 444narrows. As this happens, the clamp 420 tightens around both the hubfastener 214 and the outer diameter of the hub 401. Thus, theanti-rotate apparatus 420 may substantially limit or prevent relativerotation between the fastener 214 and the hub 401.

[0070] Hub assemblies in accordance the present invention are thus ableto provide an economical and reliable method of securely fastening awheel hub to a drive axle of a ZRT vehicle. Moreover, by incorporatinganti-rotate apparatus as described herein, hub assemblies of the presentinvention substantially reduce or eliminate relative rotation between acoaxial hub fastener and the wheel hub. In addition, hub assemblieshaving anti-rotate apparatus in accordance with the present inventionmay utilize simple hub/axle mating surfaces, e.g., opposing flats, asopposed to more complex surfaces such as keyways and tapers. Stillfurther, anti-rotate apparatus described herein are reusable. That is,they may be easily removed and reinstalled as necessary, e.g., for wheelmaintenance.

[0071] Exemplary embodiments of the present invention are describedabove. Those skilled in the art will recognize that many embodiments arepossible within the scope of the invention. Other variations,modifications, and combinations of the various parts and assemblies cancertainly be made and still fall within the scope of the invention.Thus, the invention is limited only by the following claims, andequivalents thereto.

What is claimed is:
 1. A wheel hub assembly for attachment to a driveaxle of a zero-radius-turning mower, the hub assembly comprising: a hubcomprising a central opening with one or more drive axle receivingsurfaces; a hub fastener operable to axially secure the hub to the driveaxle; and an anti-rotate apparatus comprising at least one threadedretaining fastener, wherein the anti-rotate apparatus substantiallyrestricts or prevents rotation of the hub fastener relative to the hubwhen the hub is attached to the drive axle.
 2. The hub assembly of claim1, wherein the one or more drive axle receiving surfaces comprises twodiametrically opposed flat surfaces.
 3. The hub assembly of claim 1,further comprising a bearing member positioned between a head of hubfastener and the hub.
 4. The hub assembly of claim 1, wherein theanti-rotate apparatus further comprises an anti-rotate member.
 5. Thehub assembly of claim 4, wherein the anti-rotate member may besubstantially secured to the hub by the at least one threaded retainingfastener.
 6. The hub assembly of claim 4, wherein the anti-rotatemember, when installed, clamps to one or both of the hub fastener andthe hub.
 7. The hub assembly of claim 4, further comprising a bearingmember between the hub and the anti-rotate member, wherein the bearingmember comprises one or more engagement portions operable tointerlockably engage the hub and substantially restrict or preventrelative rotation between the bearing member and the hub.
 8. The hubassembly of claim 7, wherein the bearing member further comprises ananchor portion having a threaded hole operable to receive the at leastone threaded retaining fastener.
 9. The hub assembly of claim 4, whereinthe anti-rotate member comprises a first opening and a second opening,wherein the first opening may interlockably engage the hub fastener, andthe second opening may receive the at least one threaded retainingfastener.
 10. The hub assembly of claim 9, wherein the first openingcomprises one or more notches operable to engage a head of the hubfastener.
 11. The hub assembly of claim 1, wherein the at least onethreaded retaining fastener threadably engages an anchor portion of thehub.
 12. A wheel hub assembly for coupling a wheel to a drive axle of azero-radius-turning vehicle, the hub assembly comprising: a hubcomprising a central opening having a drive axle receiving surface; ahub fastener coaxial with an axis of the drive axle, the hub fasteneroperable to axially retain the hub relative to the drive axle; and ananti-rotate apparatus comprising an anti-rotate member and at least onethreaded retaining fastener, the anti-rotate apparatus operable tosubstantially limit or prevent relative rotation between the hubfastener and the hub when the hub is attached to the drive axle.
 13. Thehub assembly of claim 12, wherein the anti-rotate member comprises agenerally flat lock tab, the lock tab having a first opening operable toengage the hub fastener and a second opening operable to receive the atleast one threaded retaining fastener.
 14. The hub assembly of claim 12,wherein the anti-rotate member comprises a clamp operable tosubstantially lock the hub fastener relative to the hub.
 15. The hubassembly of claim 12, further comprising a bearing member locatedbetween a head of the hub fastener and the hub.
 16. The hub assembly ofclaim 12, wherein the at least one threaded retaining fastenerthreadably engages the hub.
 17. The hub assembly of claim 15, whereinthe at least one threaded retaining fastener threadably engages ananchor portion of the bearing member.
 18. An anti-rotate apparatusoperable to prevent loosening of a hub fastener used to secure a wheelhub to a drive axle of a zero-radius-turning vehicle, the anti-rotateapparatus comprising: a hub fastener anti-rotate member; and a threadedretaining fastener operable to secure the anti-rotate member relative tothe hub.
 19. The anti-rotate apparatus of claim 18, further comprising abearing member positioned between the hub and a head of the hubfastener, the bearing member comprising: an engagement portion forinterlocking with a corresponding portion of the hub to substantiallyreduce or eliminate relative rotation between the bearing member and thehub; and an anchor portion comprising a threaded hole for receiving thethreaded retaining fastener.
 20. The anti-rotate apparatus of claim 18,wherein the anti-rotate member comprises a clamping device operable toclamp to a portion of the hub.
 21. The anti-rotate apparatus of claim18, wherein the anti-rotate member comprises a generally flat lock tabhaving a first opening and a second opening, the first openingcomprising portions for engaging a head of the hub fastener such thatrelative rotation between the lock tab and the hub fastener issubstantially reduced.
 22. An anti-rotate apparatus operable to preventloosening of a hub fastener used to secure a wheel hub to a drive axleof a zero-radius-turning vehicle, the anti-rotate apparatus comprisingmeans for engaging the hub fastener, and a threaded retaining fasteneroperable to secure the means for engaging the hub fastener relative tothe hub.